A general formulation for compositional reservoir simulation

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:397969

Rodriguez, F; Guzman, J ^[1]; Galindo-Nava, A ^[1]

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1. Univ. Nacional Autonoma de Mexico, Mexico City (Mexico)

In this paper the authors present a general formulation to solve the non-linear difference equations that arise in compositional reservoir simulation. The general approach here presented is based on newton`s method and provides a systematic approach to generate several formulations to solve the compositional problem, each possessing a different degree of implicitness and stability characteristics. The Fully-Implicit method is at the higher end of the implicitness spectrum while the IMPECS method, implicit in pressure-explicit in composition and saturation, is at the lower end. They show that all methods may be obtained as particular cases of the fully-implicit method. Regarding the matrix problem, all methods have a similar matrix structure; the composition of the Jacobian matrix is however unique in each case, being in some instances amenable to reductions for optimal solution of the matrix problem. Based on this, a different approach to derive IMPECS type methods is proposed; in this case, the whole set of 2nc + 6 equations, that apply in each gridblock, is reduced to a single pressure equation through matrix reduction operations; this provides a more stable numerical scheme, compared to other published IMPCS methods, in which the subset of thermodynamic equilibrium equations is arbitrarily decoupled form the set of gridblock equations to perform such reduction. The authors discuss how the general formulation here presented can be used to formulate and construct an adaptive-implicit compositional simulators. They also present results on the numerical performance of FI, IMPSEC and IMPECS methods on some test problems.

• OSTI ID: 397969
• Report Number(s): CONF-941048--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
ALGORITHMS
ITERATIVE METHODS
MATHEMATICAL MODELS
NATURAL GAS DEPOSITS
NUMERICAL ANALYSIS
PETROLEUM DEPOSITS
RESERVOIR ROCK
SIMULATION